Sony Alpha SLT-A99 In-Depth Review

The Sony SLT-A99 is the Japanese camera maker's flagship model, aimed squarely at DSLR enthusiasts who will settle for nothing less than a full frame sensor in a rugged body with a plethora of external and customizable controls. It arrives almost four years after its predecessor, the A900, the company's first full frame DSLR. You'd certainly expect significant new features given such a long gap between products and Sony has lost no opportunity to equip the A99 with every bit of electronic expertise they've incorporated into their NEX and SLT models in the interim. Whereas the A900 was a defiantly conventional SLR that would have been immediately familiar to Konica Minolta film-camera users, the A99 is something of a technological tour-de-force.

Start with a dual chip AF system, live view focus peaking, tiltable rear LCD, built-in GPS and 1080p60 movie recording plus the ability to output uncompressed video, and the contrast to the stills-only A900 couldn't be more stark aside from the A99's identical 24MP resolution. And then of course, there's the fact that with the A99 Sony has opted for an electronic, versus optical viewfinder. From a features standpoint, it's clear that Sony was out to rethink its approach to the enthusiast market and attempt to lure would-be DSLR shooters with a surfeit of technology while broadening its appeal to videographers.

Like its predecessor, the SLT-A99 enters a full frame DSLR playing field still dominated by the 'big two', so the camera's success will depend not just on its advances over the A900, but how well it competes against the Canon EOS 5D Mark III and Nikon D800. Sony may have chosen not to challenge the 36MP Nikon D800 for pixel count - somewhat of a surprise given that the D800 houses a Sony-made sensor - but has opted instead for a unique dual sensor AF system that promises more precise subject tracking along with a 6fps continuous AF burst rate.

Sony has gone to great lengths to stress the work that has gone into improving the camera's image quality. The latest 24MP sensor has been designed so that more of each photosite is light-sensitive. The electronics in front of this light sensitive region have been slimmed-down to increase the angle from which each site can receive light. These changes, combined with a design that provides a short and high-capacity path between the sensor output and the image processor, and the addition of 14-bit Raw output, should mean improved still image quality.

The rapid adoption of DSLRs by video professionals has made HD recording with manual exposure control a stock feature in even mid-range models. With the A99 though, Sony leverages its considerable video expertise by combining 1080p60 video capture with SLT-enabled phase-detection AF along with the ability to output uncompressed video over HDMI (a feature we first saw in the Nikon D800). Another well-implemented nod to the needs of run-and-gun videographers can be found in the inclusion of a 'silent controller' that allows for adjustments to made while recording without the attendant button clicks.

SLT design

The A99 is based around Sony's SLT design - a variant on the DSLR concept that uses an electronic viewfinder (EVF), rather than an optical one. Instead of having a mirror that has to flip out of the way to to take a photo, it uses a fixed semi-transparent mirror that redirects light (with negligible luminance loss) to a DSLR-style phase-detection autofocus sensor. This means live view and autofocus are always active and that the A99 can offer a consistent shooting experience whether you use the flip-out screen or the EVF. It also means the conventional 19-point phase detection focus sensor is always illuminated, along with the 109-point on-sensor array. This puts the A99 in the unique position of having dual phase-detection focus systems available at all times - an unusual feature that Sony has developed several features to exploit, including 'AF-D', its depth-map assist continuous AF feature.

This (Sony supplied) diagram shows very clearly how the SLT-A99's imaging and focussing systems are implemented (the camera shown here is the SLT-A77, but the system is identical). Light coming in through the lens is split by the fixed, semi-transparent mirror - a portion feeds the phase-detection AF sensor, and the majority hits the main imaging sensor for live view and image capture.

The decision to build a full-frame SLT camera will certainly be controversial among enthusiasts who equate a 'serious' camera with an optical, rather than electronic viewfinder. It's worth pointing out though that the A99 sports the same 2.4M dot resolution OLED 'Tru-Finder' EVF whose performance we found so impressive in our NEX-7 review. And the benefits that an EVF provides, including exposure and white balance preview, focus peaking and a customizable information overlay, all without removing the camera from an eye-level shooting position, may be enough to sway those who spends even a little time actually using it.

Preview video

This video, shot at the Photokina trade show earlier this year is taken from our previously published preview of the Sony SLT-A99.

Comments

I think this review was excellent , very honest and openminded enough to accept the EVF and the great set of amazing features that this camera gets.If I am free(I mean not need to listen to my partner when I buy a camera), I ‘d sell my D800 for this one or for the 5D3 in a heart beat.But unfortunaltey , I have to listen to my partner who hates Sony and EVF, so I guess I will have to shoot Nikon or Canon for a while.That siad , I still love A99v and I really want to buy one since I was a big fan of Sony Zeiss primes from my A900 days.The A99v is a great camera and it is probably the best camera for portrait and event work.The 85mmf1.4ZA is a super sharp lens and the 135mmf1.8ZA is even sharper and the 24f2ZA is the best 24mm I have ever shot, well done Sony and thanks for your great review.

I just don't understand the point, that the A99 empties its buffer twice as fast as Canon's EOS 5D III at Continuous Hi? Both cameras allow 6 fps, but the 5D III can shoot JPEG Large/Fine until the card is full while the Sony stops after 20 frames. When shooting RAW the 5D III can take 17 frames (like the Sony), before the frame rate switches to 2.7 fps (A99: "only" 1.7 fps). The 5D III then needs 4 seconds to empty the buffer, while the A99 needs 7.5 seconds. From my point of view, the 5D III is the faster camera. Or did I get something wrong?

I have owned previously the a55 a77 and for the last 12 months the A99 I paid £1750 new inc tax the a99 paired with the Zeiss 24-70 it a fantastic combo in fact the sony 28-75 2.8 produced stunning results but I would tell lies if i said it was on parr with the Zeiss which really pops the subject although has softness at corner edges @ 24mm is evident...Low light for my use has been great never has any problems...The flash/system shoe is the only annoyance and slight over exposure easily fixed in light room. what would I change upgrade faster AF..sensor 24mp ff is more than ample.In all I am a very happy with my a99 well done sony engineers...

There's really no way around it. This is hands down sony's best camera to date. They really should revisit this, maybe give it a sensor and/or mount of their A7s , aim to make it better @ low light than Canon 5d3 (much more cleaner than 5d3, almost 1DX spec), and get rid of the translucent mirror maybe. Keep the body as is, make it mirrorless with around 15-18 megapixel and give it FPS of 8-11.

Waiting for 18Mp, Mirrorless(or at least the ability to lift the mirror.., somehow...) with high speed AF and low light sensitivity AF down to -3EV[currently seems impossible...]Touch screen with focus select and AF by touch.

Alternatively to 18Mp - make 36mp with BSI, removing the anti-alias filter and allowing the semi-transparent mirror to be moved out of the way - or else simply have magnificent focus with the sensor itself....wihtout the mirror.....sigh!!!!

Something that amazes me about the A99 is the fact that it handles high ISO better than the new Nikon D600 and D610 cameras. I just found this out by looking at the ISO 6400 samples here on DPreveiw in their studio shot comparison tool: http://www.dpreview.com/reviews/studio-compare#baseDir=%2Freviews_data&cameraDataSubdir=boxshot&indexFileName=boxshotindex.xml&presetsFileName=boxshotpresets.xml&showDescriptions=false&headerTitle=Studio%20scene&headerSubTitle=Standard%20studio%20scene%20comparison&masterCamera=nikon_d600&masterSample=dsc_4526_03&slotsCount=4&slot0Camera=nikon_d600&slot0Sample=dsc_4526_03&slot0DisableCameraSelection=true&slot0DisableSampleSelection=true&slot0LinkWithMaster=true&slot1Camera=sony_slta99&slot1Sample=dsc00049&x=-0.378464142966364&y=0.34409159041539195

Make sure you look at the playing card, after you pick which cameras you want to compare and set the ISO selection box to ISO 6400 (or whatever ISO you want to compare).

About SLT & SLR cameras, If following two comments (from dpreview) are conflicting each other ? During bursts shooting SLT cameras can see the frames or can not see ? maybe I'm misunderstood. Thanks !1, Unlike ordinary DSLR cameras, SLT cameras by Sony use Translucent Mirror technology that directs light onto the main image sensor as well as a separate autofocus sensor. This means that subjects stay sharply focused at all times as you compose scenes with the tilt-angle LCD or through the high-resolution, high-contrast OLED Tru-Finder. And with no moving mirror to slow you down, you’ll enjoy non-stop live image preview during speedy burst shooting or while you’re recording Full HD video.2, One distinct disadvantage to current EVF technology is that when shooting bursts at higher frame rates, you are not seeing a live preview, rather the frames you have just captured. This can make camera panning (to follow a fast moving subject) virtually impossible to do with any accuracy.

This review fails to show the I/O connectors! What is under those flaps? Most importantly where is the PC-sync terminal???? If there isn't one, I'll keep looking for a different camera. Please clarify.